U.S. Detected Iranian Plot to Kill Trump Separate From Last Weekend’s Shooting

U.S. intelligence agencies were tracking what they considered a potential Iranian assassination plot against former President Donald J. Trump in the weeks before a gunman opened fire last weekend, several officials said on Tuesday, but they added that they did not believe the threat was related to the shooting that wounded Mr. Trump.

The intelligence had prompted the Secret Service to enhance security for the former president before his outdoor campaign rally in Butler, Pa., on Saturday, officials said. Yet whatever additional measures were taken did not stop a 20-year-old local man from clambering on top of a nearby warehouse roof to shoot at Mr. Trump, grazing his right ear and coming close to killing him.

The Trump campaign was told about the threat not long before Saturday’s shooting, according to a person briefed on the situation.

The latest threat stems from Iran’s longstanding desire to take revenge for the strike ordered by Mr. Trump in 2020 that killed Maj. Gen. Qassim Suleimani, the Iranian security and intelligence commander responsible for the deaths of hundreds of American troops over the years. Reported Iranian threats against Trump administration officials like Mike Pompeo, the former secretary of state, and John R. Bolton, the former national security adviser, have resulted in government security details even after they left office.

“As we have said many times, we have been tracking Iranian threats against former Trump administration officials for years, dating back to the last administration,” Adrienne Watson, a spokeswoman for the National Security Council, said in a statement. “These threats arise from Iran’s desire to seek revenge for the killing of Qassim Suleimani. We consider this a national and homeland security matter of the highest priority.”

Ms. Watson emphasized that the Iranian plot was separate from the Butler assassination attempt. “The investigation of Saturday’s attempted assassination of former President Trump is active and ongoing,” she said. “At this time, law enforcement has reported that their investigation has not identified ties between the shooter and any accomplice or co-conspirator, foreign or domestic.”

CNN previously reported on the Iran threat information. Alejandro N. Mayorkas, the secretary of homeland security, hinted at a threat emanating from overseas during a briefing on Monday at the White House.

“The threat landscape is very dynamic, both domestically with the rise of domestic violent extremism,” he said, adding that “of course, we have seen the foreign threat environment increase as well.”

David E. Sanger and Maggie Haberman contributed reporting.